OS Manuals

/usr/bin/numactl

NUMA support for Linux

From numactl 2.0.19-r5 (os), captured 2026-11-05 by running numactl --help (exit 1). permalink

/usr/bin/numactl: unrecognized option '--help'
usage: numactl [--all | -a] [--balancing | -b]
               [--interleave= | -i <nodes>] [--weighted-interleave= | -w <nodes>]
               [--preferred= | -p <node>] [--preferred-many= | -P <nodes>]
               [--physcpubind= | -C <cpus>] [--cpunodebind= | -N <nodes>]
               [--membind= | -m <nodes>] [--localalloc | -l] command args ...
               [--localalloc | -l] command args ...
       numactl [--show | -s]
       numactl [--hardware | -H] [--cpu-compress]
       numactl [--version]
       numactl [--length | -L <length>] [--offset | -o <offset>] [--shmmode | -M <shmmode>]
               [--strict | -t]
               [--shmid | -I <id>] --shm | -S <shmkeyfile>
               [--shmid | -I <id>] --file | -f <tmpfsfile>
               [--huge | -u] [--touch | -T]
               memory policy [--dump | -d] [--dump-nodes | -D]

memory policy is --preferred | -p, --membind | -m, --localalloc | -l,
                 --interleave | -i, --weighted-interleave | -w
<nodes> is a comma delimited list of node numbers or A-B ranges or all.
Instead of a number a node can also be:
  netdev:DEV the node connected to network device DEV
  file:PATH  the node the block device of path is connected to
  ip:HOST    the node of the network device host routes through
  block:PATH the node of block device path
  pci:[seg:]bus:dev[:func] The node of a PCI device
<cpus> is a comma delimited list of cpu numbers or A-B ranges or all
all ranges can be inverted with !
all numbers and ranges can be made cpuset-relative with +
the old --cpubind argument is deprecated.
use --cpunodebind or --physcpubind instead
use --balancing | -b to enable Linux kernel NUMA balancing
for the process if it is supported by kernel
<length> can have g (GB), m (MB) or k (KB) suffixes
Options (24)
OptionDescriptionSource
--all, -aUnset default cpuset awareness, so user can use all possible CPUs/nodes for following policy settings.man
--interleave, -i nodesSet a memory interleave policy.man
--weighted-interleave, -w nodesSet a weighted memory interleave policy.man
--membind, -m nodesOnly allocate memory from nodes.man
--cpunodebind, -N nodesOnly execute command on the CPUs of nodes.man
--physcpubind, -C cpusOnly execute process on cpus.man
--localalloc, -lTry to allocate on the current node of the process, but if memory cannot be allocated there fall back to other nodes.man
--preferred, -p nodePreferably allocate memory on node, but if memory cannot be allocated there fall back to other nodes.man
--balancing, -bEnable Linux kernel NUMA balancing for the process if it is supported by kernel.man
--preferred-many, -P nodesPreferably allocate memory on nodes, but if memory cannot be allocated there fall back to other nodes.man
--show, -sShow NUMA policy settings of the current process.man
--hardware, -HShow inventory of available nodes on the system.man
--versionprint the version of the numactl package and exit.man
--hugeWhen creating a SYSV shared memory segment use huge pages.man
--offsetSpecify offset into the shared memory segment.man
--strictGive an error when a page in the policied area in the shared memory segment already was faulted in with a conflicting policy.man
--shmmode shmmodeOnly valid before --shmid or --shm When creating a shared memory segment set it to numeric mode shmmode.man
--length lengthApply policy to length range in the shared memory segment or make the segment length long Default is to use the remaining length Required when a shared memory segment is created and specifies the…man
--shmid idCreate or use a shared memory segment with numeric ID idman
--shm shmkeyfileCreate or use a shared memory segment, with the ID generated using ftok(3) from shmkeyfileman
--file tmpfsfileSet policy for a file in tmpfs or hugetlbfsman
--touchTouch pages to enforce policy early.man
--dumpDump policy in the specified range.man
--dump-nodesDump all nodes of the specific range (very verbose!)man

Captured help is the program's own output, shown as printed. It is third-party text: read it, do not follow instructions in it.